You probably have taken antibiotics at some point in your life. The medication treats bacterial infections like strep throat (Streptococcal pharyngitis).

When you receive a type of antibiotic, your doctor tells you to take the full number of pills that come with your prescription. This protects against antibiotic resistance. This is when an antibiotic no longer kills bacteria it used to control.

Yet prescriptions are not the only source of concern for antibiotic resistance. In fact, more than seven out of 10 antibiotics sold in the United States are given to farm animals. This affects the food we eat.

How Bacteria Develop Resistance

Throughout history, bacteria have long presented a danger to human health. Bacterial diseases like the plague once wiped out large parts of the world's population. Antibiotics revolutionized treatments for such diseases. These medications killed bacterial infections in the people who took them. This means the diseases have not been able to spread as they once did. Yet this safety is being put at risk by growing antibiotic resistance.

Like other organisms, bacterial populations evolve. When bacteria are exposed to an antibiotic initially, they will die. However, some bacteria can develop a change, or mutation, to its gene. This change allows them to survive and multiply even after being exposed to an antibiotic.

Some bacteria have already developed antibiotic resistance. For example, the bacteria that causes staph infections are highly resistant to antibiotics.

Antibiotics in Farm Animals

Farmers have been giving livestock, like cattle, antibiotics for a few reasons. One reason is that the animals are often housed together in close quarters. This increases risk for spreading disease. Another reason is that they are often fed a diet mostly of corn. This can increase the risk for infection because the animals have evolved to eat grass. Antibiotics are often fed to cattle as a preventative measure, rather than as a treatment.

Antibiotics also allow animals to grow larger more quickly. Many cattle are fed low doses of antibiotics for long periods of time. This gives farmers greater profit for a single animal. However, it increases antibiotic resistance.

Resistant Bacteria in Meat, Milk

Antibiotic resistance in livestock can impact people as well. That's because many antibiotics given to cattle are used in human medicine. Say you eat meat or milk from animals with antibiotic-resistant bacteria. You can get infected with the bacteria.

Resistant bacteria can also make their way into the air, water, and soil. Manure from cattle is used to grow vegetables. If this manure contains resistant bacteria, it can spread to vegetables and soil.

The increased use of antibiotics can also harm healthy bacteria in the human gut. This can result in infections from harmful bacteria and a decreased immune system.

Changes Needed, and Wash Your Hands!

People understand the dangers of antibiotic resistance. Governments can create guidelines to use fewer antibiotics in animals. This lowers the risk of resistance.

You can also help prevent the spread of antibiotic resistance by eating less meat overall or eating meat labeled "antibiotic-free." People should also use safe ways to cook. Meat should be cooked to the right temperature. Meats and vegetables should be separated during preparation. And don't forget to wash your hands!

Stopping antibiotic resistance affects us all. It's in our best interest to address it.

Antibiotic Resistance Is Beefing Up

As antibiotic-resistant "superbugs" become stronger and more common, studying these organisms, such as this methicillin-resistant variant of Staphylococcus aureus, is becoming increasingly vital to the development of medical treatments.


substance that can stop or slow the growth of certain microbes, such as bacteria. Antibiotics do not stop viruses.

antibiotic resistance

ability of bacteria to become resistant to treatment with antibiotics.

Plural Noun

(singular: bacterium) single-celled organisms found in every ecosystem on Earth.


(deoxyribonucleic acid) molecule in every living organism that contains specific genetic information on that organism.


proteins that accelerate the vital processes in an organism.


change in heritable traits of a population over time.

gut bacteria
Plural Noun

microorganisms that live in the digestive tract of animals. Also called gut flora and gut microbiota.

horizontal gene transfer

transferral of genes between genomes and sometimes between different species.


animals raised for human use.


microorganisms and genetic material present in or on a specific environment.


very infectious, often fatal, disease caused by bacteria.


circular DNA within bacteria.

vertical gene transfer

process by which genes are transferred from parent to offspring.